1. Field of the Invention
The invention relates to a measuring apparatus for measuring or adjusting the relative position between two objects, for example, the bed and the carriage of a processing or measuring machine. The measuring apparatus according to the invention includes a measuring scale, and a reading unit for the measuring scale which is connected in a hinge-like manner by means of a coupling to an object whose relative position is to be measured and to auxiliary guide means separated from the guide means for the measured object. The measured object can be a carriage of a processing or measuring machine. The reading unit can be a component of an optical, electrical, or photoelectrical longitudinal measuring apparatus.
2. Description of the Prior Art
In the prior art measuring apparatus are provided whereby the linear dimension of an object is optically measured by reciprocal movement of a measuring scale and reading unit, one of which is secured to the measured object. Optical longitudinal measuring apparatus of this type are broadly disclosed in West German Gebrauchsmuster No. 75 21 395 and U.S. Pat. No. 3,816,003 (Litke) issued June 11, 1974. These measuring apparatus typically include a reading unit which is guided along an auxiliary guide means mounted separately from a machine or measured object guide means, and additionally require an articulated coupling to the object to which the reading unit is connected. Such a coupling must be free from play to avoid any adverse effect upon the measuring precision of the apparatus. In the prior art couplings used in measuring apparatus of this type are costly and contain technical deficiencies which diminish measuring precision.